Carbureter for internal-combustion engines.



0; 1).. LUCAS.

CARBU RETER FOR INTERNAL COMBUSTION ENGINES.

APPLICATION 111.50 MAR. 18. 1911.

1, 1 50,782. Patented Aug. 17 1915 1&1. 4 6

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OWEN DAVID LUCAS, OF WESTMINSTER, LONDON, ENGLAND.

GARBUR-ETEB FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Aug. 17, 1915.

Application filed March 18, 1911. Serial No. 615,294.

To aut /10m it may concern Be'it known that I, OwnN DAVID Lucas, a subject of His Majesty King of England, residing at 39 Victoria street, Vestmm'ster, in the county of London, Kingdom ot' England, have invented certain new and useful Improvements in Carbureters for Internal- Combustion Engines, of which the tollowing is a specification.

This invention has reference to improvements in carbureters tor internal combustion engines and its object i s to provide a means whereby proper quantities of air and liquid hydrocarbon are provided under all conditions of working in the internal combustion engine.

The invention comprises two chambers in communication one with the other through one or more small orifices and into one of the chambers the fuel passes by way of a jet, the other chamber communicating directly with theinduction port of the engine. Botli chambers are provided with air ports and there is provision for controlling the effective sizes of these air ports for a purpose which will hereinafter appear.

The invention will be best understood from a consideration of the following de tailed description taken in connection with the accompanying drawings forming a part of this specification, with the understanding, however, that theaarrangements indicated in the drawings are susceptible of various changes and modifications, wherefore the invention is not limited to any exact conformity with the particular showing of the drawings.

In the drawings :-Figure 1 illustrates diagrammatically a carbureter with connections to an engine, and arranged in accordance with the present invention. Fig. 2 is a similar view showing a modifiedarrangement; Fig. 3 is a diagrammatic showing of an arrangement of ports controlled by one sliding throttle and indicating relative shapes oi the ports to give the correct mixture for all positions of the throttle.

In the (lrawings'therc is indicated a chamber a in which the air and hydro-carbon fuel become intermixed and which may, therefore, be termed the mixing chamber. This chamber a. is provided with an air port 0. At one side of the. chamber a in the centrally located within the chamb r (i, as in Fig. 2, is another chamber 1 in the lower portion of which there is located a jet 9', wherefore the chamber (Z may 'for convenience be termed the jet chamber. Liquid hydro-carbon is directed to the jet j by any suitable means, such as a constant level float chamher or its equivalent. The chamber d is provided with an air port a, while the chamber a is indicated -as connected to the interior of the cylinder L of an engine by a pipe 7 and the chamber a communicates with the chamber (1 through one or more small orifices, two such orifices Z and m being indicated in the drawings, but it will be understood that a greater number of orifices may be provided if desired.

In Fig. 1 the air ports 0 and c are simultaneously controlled by a common sliding throttle f, the arrangement being such that when one port is opened the other port is closed. In Fig. 2 the air ports 0 and e are controlled by respective throttles c and c operated by interconnected levers in such a way that when one is opening the other is closing.

No attempt is made to show in Fig. 1 the relative shape and size of the air ports 0 and 6, while in Fig. 3 a shape and relative size of the two air ports is indicated, which shape has been found in practice to give good results, but the shape of these ports may be varied in any suitable manner so long as there is maintained the desired relationship between the areas of the ports opened for agiven displacement of the throttle f. l urthermore, any suitable type. of valve may be employed, whereby one port will be reduced in effective area as the other port is being enlarged in efi'ective. area.

\Vhen the engine piston is moving on the suction stroke there is produced within the chamber a sub-atmos )heric conditions, and sub-atmospheric conditions are also pro rlzlced in the chamber (Z since the two chambers are in constant commun' ration through the orifices l and m. The result of this action is that fuel is drawn into the chamber (1 through the 7' and from this chamber the fuel passes through the orifices in its wall to the chamber (1., being ultimately drawn through the pipe 7', into the engine cylinder. Assuming that both air ports c and c are open. the suction produced in the chamber (1, causes an inflow of air through the port 0 into the chamber (A to there intermix with the fuel entering the chamber through the orifices Z and m, and the fuel entering the chamber d may also become intermixed to an extentwith air entering the chamber d through the port e.

Theair port ofthe chamber a is so situated that when it is closed 'the degree of vacuum in the mixing chamber a caused by the suction of the engine tends to increase, and therefore because the chamber a is in communication with the chamber cl through the orifices Z and m the same condition would arise in the chamber d to increase the suction at the jet j were its tendency not counteracted by the opening of the port 6, which may, therefore, be termed the jet controlling-port, as the port 0 which may be termed the air port, is closed, and, of course, the contrary action takes place when the air port 0 is opened and the jet controlling port a is closed. The action of the air port 0 and its throttle on the jet is opposite to that in which a throttle operates when it is placed, as is customary, in the induction pipe between the jet and the engine.

By the present invention properquantities of air and hydro-carbon areunder all'conditions of running delivered to the engine. To increase the amount of fuel the jet controlling port e is moved toward theclosed position, Wherefore the action of suction'is more pronounced in the chamber (l and more I fuel is drawn through the jet 7'. At the same time more air is admitted to the chamber a to compensate for the increased supply of hydro-carbon fuel. When theport c is made effectively smaller the port 6 is made effectively larger, and consequently the action of suction on the jet 7' is correspondingly lessened, so that less fuel is delivered into the chamber d and ultimately'into the chamber a where a smaller amount of air is intermixed therewith.

The present invention has to do with the obtaining of correct proportions of air and hydro-carbon, wherefore no means ha ve been shown or described for atomizing and properly'mixing the hydro-carbon with the air before it is introduced into the engine cylinder. Generally it will be necessary to associate some appropriate means for this purpose with the arrangement shown in the drawings, but as any well known means may be employed for this purpose. it is not deemed necessary to illustrate and describe the same. Since by the present invention the requisite proportions of air and hydrocarbon are provided at all times vand under all conditions of running. the particular form of atomizer which may be employed is of no especial moment.

In a carbureter constructed in accordance with the present invention there is no throttle between the mixing chamber and the engine and a throttle is placed on the .atmospheric' side of the main air inlet to conntense trol the air supply. Tlie aiiibunt of hydrocarbon fuel required for any degree of opening of the main. throttle is measured by c'ontrolling the amount of suction on the jet, thus actually measuring the hydro-carbon in the liquid state before it is vaporized.

\Vhile the part j has herein beentermed a jet, this term is used for convenience of description and not in any sense limited to a finely graded orifice such as is commonly used in carbureters.

The effect of the throttle on the atmosdegree of vacuum in the mixing chamber, 1f unmodified, would act directly on the jet so, a

or fuel inlet, thereby increasing the amount of fuel sucked in, and proportioned to the closing morementot' the main air throttle. The chamber (l, however, communicates with the atmosphere through an air port which is opened as required to admit suflicient air to conteract the sub-atmospheric pressure within the chamber (l to just that extentlas will cause the sucking oflthe correct amount By.

of hydro-carbon into the chamber (Z. properly proportioning theopenings 0 and e and the throttling means therefor the openings may be simultaneously opened and closed in inverse order. Since air is used to counteract the excess of suction on the fuel inlet, such air and the necessary hydrocarbon pass together through the fine orifices from the jet chamber '1! into the mixing chamber a-,,the eli'ect being to atomize the hydro-carbon and as the. hydro-carbon spray so formed enters the mixing chamber where the degree of vacuum is always higher than that in the jet chamber, for the more the main air throttle is closed the higher is the degree of vacuum, the already atomized hydro-carbmi is thereby more readily converted into a true vapor or gas. The degree of vacuum inthe mixing chamber is the least when the main'air port c is wide open and then the greatest quantity of hydro-carbon is required. The size of the jet and jet chamber orifices are so adjusted as to pass sutiicient hydro-carbon with its automizing air to give a correct mixture, when the main air port c is in the wide open position. Since the amount of hydro-carbon drawn into the'carbureter is controlled by the amount of air admitted through the inlet sit follows that so long as the orifices are large enough the exact amount of hydroca 'bon required is determined by the openin at tlieinlet c. wherefore the jet and jetchamber orifices may be standardized and require no further adjustment. For all other positions of the main air throttle less air is admitted to the mixing chamber and consequently less hydro-carbon is required, and it follows that the suction in the jet chamber should never exceed that necessary when the main air port is wide open, but must decrease as the main air throttle is moved toward the closed position. Therefore, the more'themain air port is closed the more the jet chamber air port must be opened.

\Vith any constant position of the main air throttle, and therefore also of the jet air throttle connected to it, the degree of vacuum in the mixing chamber will vary as the speed of the engine, but any variation in sub-atmospheric pressure in the mixing chamber is as once communicated to the jet chamber and jet, and experience has shown that the degree of vacuum in both chambers is correctly and automatically proportioned so as to give the correct mixture, and this arrangement may be made the more absolute by placing one or more of the orifices between the jet chamber and the mixing chamber at a higher level than the others, that is, nearer the jet control air inlet, while the rest are nearly on a level with the top of the jet.

T he adjustable throttling means described provides a control which may be used for ordinary governing purposes.

What is claimed is 1. A carburetor for internal combustion engines, provided with separate chambers, one of which has means for direct communication with the engine and the other having means wholly therewithin for the introduction thereinto of hydrocarbon fluid, each chamber being also provided with an air port opening directly to the atmosphere, and throttling means for the air ports movable to enlarge the effective area of the air port of one chamber simultaneously with the cutting down of the eli'ective area of the air port of the other chamber, or the reverse,

and said chambers having constricted means of communication adjacent to the means for the introduction of hydrocarbon fluid and remote therefrom.

2. A carbureter for internal combustion engines comprising two separate chambers each provided with an air port opening directly to the atmosphere, one of the chambers having an inlet for fuel wholly therewithin and at a point in the chamber remote from the air inlet thereof, and means for simultaneously varying the ett'ective areas of the air ports in inverse relation one to the other, said chambers having means of communication of relatively small area both adjacent to the fuel inlet means and to the air inlet of the fuel receiving chamber.

'5. A carbureter for internal combustion engines having two sepa ate chambers each provided with an air port and one of the chambers having means wholly therewithin and individual thereto for the introduction of fuel, the chambers beingin constant communication through orifices of relatively small area and the air ports being of'different sizes. 1

r. A carbureter for internal combustion engines having two separate chambers interconnnunicating through orifices of relatively small size, each chamber being provided with an air port and one of the chambers having means individual thereto and wholly inclosed therein for the introduction of liquid fuel.

A carburetor for internal combustion engines having two separate chambers interconununicating through orifices of relatively small size, both chambers being provided with air ports of larger size than the orifices, and one ot' the clmmbers having means individual thereto and wholly therewithin for the introduction of liquid fuel, the air ports being provided with means for regu lating their etl'ectve area in inverse relation one with the other.

(i. In a carburetor for internal combustion engines, means for delivering proper quantities of air and hydrocarbon under all con ditions of running, consisting of two separate chambers, one provided with means wholly therewithin tor the introduction of hydro-carbon liquid, and each chamber having an air port, the chambers being provided with one or more constantly open orifices of relatively small area with respect to the air ports and constituting a means of intercommunication between the chambers and throttling means for the air ports related thereto to enlarge the eltective area of one air port while reducing the effective area of the other air port, and vice versa.

'7. A carburetor for internal combustion engines having means for causing delivery of proper quantities of air and hydro-carbon under all conditions of running of the engine, comprising two comn'iunicating chambers with one of the chambers provided with means for conununic'ation with the engine, and the other chamber being provided with means wholly therewithin for the introduction of liquid hydro-carbon, each chamber being provided with an air port, and throttling means for the air ports constituting the sole throttling means for the carburetor.

S. In a carbureter for internal combustion engines. means for delivering proper quantities oi nd hvdro-carbon under all conditions of running, consisting of two separate chambers, one provided with means wholly therewithin for the introduction of hydrocarbon liquid and an air port at a pointout of line with the travel of the hydro-carbon from one chamber to the other. and the other chamber also being provided with an air 9 rectly to the atmosphere, and throttling port, the two chambers communicating one with the other through a plurality of small orifices located near the inlet means for thehydro-carbon, and also near the air ports, and throttling means for the airports related thereto to enlarge the effective area of one air port while reducing the effective area of the other air port, and vice versa- 9; A carbureter for internal combustion engines'having two separate chambers each provided witl aan air port,'and one of the chambers haviitg means individual thereto and, wholly therewithin for the introduction of fuel, the chambers being separated by a wall having a constantly open orifice therethrough of relatively small. area and located near the means for the introduction of fuel, and an orifice of relatively small area located near the means for the introduction of air into the chamber into which the fuel is introduced.

10. A carbureter for internal combustion engines provided with separate constantly communicating chambers, one of which is provided with means for direct connection to the engine and the other With means wholly therewithin for the introduction of hydrocarbon fuel by suction, both chambers being provided with air ports'opening dimeans therefor movable to enlarge the effective area of the air port of one chamber simultaneously with thecutting down of the efi'ective area of the air port of the other chamber, or the reverse, the fuel inlet being located at a relatively low point in the chamber containing it.

' .11. The method of supplying proper quantities of air and hydrocarbon fuel under all conditions of running to a carbureter for an explosion engine, which consists in establishing, bythe suction of the engine, subatmospheric pressureiin separate communicating chambers, andhndrawing thereby hydrocarbon fuel at a relatively low point in one of the chambers, and introducing air didesired amount of fuel'and the atmospheric air entering the other chamber being in quantity directly proportional to the desired amount of fuel. I

In testimony whereof I have hereunto set my hand in presence of two subscribingwib nesses this day of 1911. v

OWEN DAVID LUCAS. Witnesses:

: ROBERT POLLOCK, J. S. \Vrrunns. 

